This proposal deals with the development of structure-activity equations (models) for the Draize skin and eye irritancy tests. We have previously developed such models for rat oral LD50, mutagenicity, carcinogenicity, teratogenicity, and biodegradability. The principles used in the development of these models are to be applied to the development of similar models for the Draize tests. In these models a set of chemicals for which the endpoints have been measured are used to form the basis of regression equations. The independent parameters include substructural fragments, and physical parameters such as octanol-water partition coefficient, molecular weight, molecular area and volume, molecular connectivity indices, etc. The majority of the data for the model will be derived from RTECS (Registry of Toxic Effects of Chemical Substances), with the remaining data being obtained from the U.S. Army and a directed survey of the literature. The successful outcome of this research would mean that pure compounds which have so far not been tested by the Draize test would not need to be tested in animals. Instead, the alternative of estimating the effects through the SAR models would be substituted.